These risk ratings take many details into account, such as country of origin, how travel to the United States was funded, and the visitor's driving record. Other more mundane details also factor in, such as where the person is sitting on the flight and what they ordered for their meal.

The existence of such a system was first discovered by the public in November 2006, when a mention of it appeared in the Federal Register.

Bruce Schneier; "There is something un-American about a government program that uses secret criteria to collect dossiers on innocent people and shares that information with various agencies, all without any oversight. It's the sort of thing you'd expect from the former Soviet Union or East Germany or China. And it doesn't make us any safer from terrorism."